| Literature DB >> 27891746 |
Alison Levens1, Adam Ametovski1, David W Lupton1.
Abstract
Herein we report the enantioselective (4+2) annulation of donor-acceptor cyclobutanes and unsaturated acyl fluorides using N-heterocyclic carbene catalysis. The reaction allows a 3-step synthesis of cyclohexyl β-lactones (25 examples) in excellent chemical yield (most ≥90 %) and stereochemical integrity (all >20:1 d.r., most ≥97:3 e.r.). Mechanistic studies support ester enolate Claisen rearrangement, while derivatizations provide functionalized cyclohexenes and dihydroquinolinones.Entities:
Keywords: N-heterocyclic carbenes; cyclohexanes; donor-acceptor cyclobutanes; enantioselective catalysis; organocatalysis
Year: 2016 PMID： 27891746 DOI： 10.1002/anie.201609330
Source DB: PubMed Journal: Angew Chem Int Ed Engl ISSN： 1433-7851 Impact factor: 15.336